<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>案例：计数器</title>
</head>
<body>
<div id="app">
  <h2>当前计数：{{counter}}</h2>
  <<!--button v-on:click='counter++'>+</button>
    <button v-on:click='counter--'>-</button>-->
  <button v-on:click="add">+</button>
  <button @click="sub">-</button>
</div>
<script src="../js/vue.js"></script>
<script>
  const obj = {
    counter: 0
  }

  const app = new Vue({
    el: '#app',
    data: obj,
    methods: {
      add: function () {
        console.log('计数器相加');
        this.counter++
      },
      sub: function () {
        console.log('计数器相减');
        this.counter--
      }
    },
    created: function () {
      console.log('created函数');
    },
    mounted: function () {
      console.log('mounted函数');
    }

  })
</script>
</body>
</html>
